Surgical instrument for skin grafting



De@ 29 ma H. M. BRQWN ET AL.

SURGICAL INSTRUMENT FOR SKIN -GRAFTING Filed Aug. 25, 1947 2f if 2a 21 1 am4 INVENTORS. Hna ffzv M. Bean/N man /N'z'wfvf/S,

Patented Dec. 28, 1948 SURGICAL INSTRUMENT FOR SKIN GRAFTING Harry M. Brown, Indianapolis, and Milford Barron, Anderson, Ind.; Irene Brown administratrix of said Harry M. Brown, deceased, assignors to Irene Phillips Brown, Indianapolis, Ind.

Application August 25, 1947, Serial No. 770,360

Our invention relates to machines for removing sections of skin for use in skin grafts. It is the object of our invention to provide such a machine which can be operated easily and effectively to remove skin-portions of accurately predetermined width and thickness and of any desired length; and to do so with a minimum of effort and of danger.

In carrying out our invention, we provide a hand-held main frame in which there is a rotatable shaft which oscillates a knife blade parallel to the blade edge; and behind that oscillating blade we provide a foot-plate which bears upon the skin, while in front of the blade we provide a micro-adjustable pressure plate of special shape to smooth out the skin just in advance of `the blade; and we provide micro-adjusting screws for adjusting separately the two ends of that pressure plate with relation to the plane of the foot-plate; and we provide a pair of guide plates which underlie the ends of the blade and pressure-plate and foot-plate and are adjustable toward and from each other to vary the width of the skinportion being removed.

The accompanying drawing illustrates our invention: Fig. 1 is a plan of a dermatome embodying our invention in its preferred form; Fig. 2 is a section on the line 2--2 of Fig. 1; Fig. 3 is a bottom View of the front end of the dermatome of Figs. 1 and 2; Fig. 4 is a front elevation of said dermatome; Fig. 5 is a fragmental transverse section on the line 5 5 of Fig. 1, to show the micro-adjustment of the pressure-plate; Fig. 6 is a fragmental detail showing the eccentric-end-slot drive for the carriage; and Fig. 7 is a side elevation on a reduced scale of a modification in which the carriage is driven by a motor mounted in the handle.

A main frame I has a foot-plate II connecting its two side members and arranged to bear upon the skin to be removed, and an operating handle I2 extending obliquely upward and to the rear for convenient grasping by the surgeon. Extending longitudinally through the handle I2 is a flexible drive shaft I3, which extends out of the rear end of the handle I2 to a suitable driving motor I4, conveniently an electric motor. A transversely movable carriage I is mounted in the frame I0 on two cross bars I6, and has an oscillating driving connection to the flexible shaft I3; which flexible driving connection may be a disk I'I eccentrically mounted on the forward end of the shaft I3 and loosely fitting in a, transverse slot I8` in the rear edge of the carriage I5; so that as the shaft I3 rotates it moves the carriage I 5 back and forth on the cross bars I6. Instead of having a 13 Claims. (Cl. 12S-305.5)

iiexible shaft I3 driven by a separate motor I4, we may if desired mount an electric motor I 4a directly on the frame I0 so that its casing serves as the handle, with such motor Ma suitably controlled by a switch I9.

Removably mounted on the transversely oscillating carriage I5 is a blade 20, positioned in place by pins 2| extending upward from the carriage I 5 through holes in the blade 20 and held in place on the carriage by screws 22. The blade 20 is thus accurately and rmly held in place on the carriage I5, and oscillates with it. The front edge of the blade 20 lies just ahead of and slightly above the front edge of the foot-plate I I; but desirably does not quite touch such foot-plate, as is clear from Fig. 2.`

Just infront of the blade 2D is a pressure-plate 25` Rotatably movable but axially xed in each end of this pressure-plate 25 is a screw 26, which is screw-threadedly received in a boss 21 of the frame` ID and which projects upwardly through and beyond said boss where it is provided with a knurled head 28. The head 28 has a skirt which extends downward and surrounds the upper end of the boss 21. To aid in accurately positioning the associated end of the pressure-plate 25, the skirt of the head 28 is desirably provided WithA micrometer markings to cooperate Iwith an index on the boss 21. By adjusting the two screws 26. the two ends of the pressure-plate 25 may be separately adjusted normally to the plane of the foot-plate I6 and to the cutting plane of the knife 21|. Preferably, the upper end of each screw 25 is surrounded by a compression spring 29 acting between thehead 28 and the associated boss 27 to take up lost-motion and contribute to accurate positioning of the pressure-plate 25.

The under face of the foot-plate I I is provided with ribs 30 extending across said foot-plate in the direction of ltravel, or perpendicular to the cuttingedge of the blade 2U. These ribs 30 press down the skin on which they rest, but the spaces between the ribs permit the skin to bulge upward between the ribs 30. The spaces between the ribs extend from the rear edge of the foot-plate I I tov movably mounted on a second pair of cross bars f 36 of the frame I0. These cross bars are substantially at the very front of the frame IU, and one above the other; and the guide plates 35 have. upward extensions 31 by which they are mounted on those cross bars 36. Lyin-g between the two cross bars 36 is a right-hand-left-hand screw 38 which cooperates with the two guide plate eX- tensions 31, so that as the screw 3E is turned by its knurled head 39 the two guide plates are moved toward or from each other and toward or from the mid-line of the dermatome. This gives an accurate predetermination of the width of the skin portion being removed; for the Width of the cut is determined by the distance between the adjacent edges of the two guide plates 35.

In operation, the knurled head 3B is turned to adjust the guide plates 35 to give the desired width of the cut; and the two nuts 28 are adjusted to move the pressure-plate 25 to give the desired depth of the out. When so adjusted, and the motor lll or Ilia put in operation, the surgeon may move the dermatome forward, and remove a skin portion of desired width and thickness and of such length as he desires. The ribs on the pressure-plate and foot-plate are effective in preventing lateral movement of the skin under the drag imposed on it by the reciprocating knife. To make the ribs as effective as possible in attaining that end, they should have well-dened skinengaging edges which extend as close to the cutting-edgev of the knife as is permitted by the necessity for clearance and the advsability that the skin be held flat over the cutting edge.

We claim as our invention 1.

l. A dermatome comprising a hand-.holdable frame having a foot-plate to bear against the skin, a knife mounted in said frame to oscillate transversely therein and having a Cutting edge in front of and substantially in the plane of said foot-plate, a shaft rotatably mounted in `said frame and having a driving connection to said knife to oscillate the latter, and a pressure-plate mounted on said .frame to engage the skin in front of the knife, the skin-engaging face of -said footplate being provided with parallel ribs transverse to the cutting edge of the knife.

2. A dermatom-e comprising a hand-holdable frame having a foot-plate to bear against the skin, a knife mounted in said frame to oscillate transversely therein and having a cutting edge in front of and substantially in the plane lof said foot-plate, a shaft rotatably mounted in said frame and having a driving connection to said knife to oscillate the latter, and a pressure-plate mounted on said frame to engage the skin in front of the knife, the skin-engaging face. of said pressure-plate being provided with parallel ribs transverse tothe cutting edge of the knife.

3. A dermate-me comprising a hand-holdable frame having a foot-plate to bear aga-inst the skin, a knife mount-ed -i-n said frame to oscillate transversely therein and having a cutting edge in front of and substantially in the plane of said foot-plate, a shaft rotatably mounted .in `said frame and having a driving connection to said knife to oscillate the latter, and a pressure-plate mounted on said frame to engage the skin in front of the knife, the skin-engaging face of said pressure-plate being provided at its front portion with parallel ribs transverse to the cutting edge of the knife but having an unribbed rear portion close to the knife-edge.

4. A dermatome comprising a hand-holdable frame having a foot-plate to bear against the skin, a knife mounted in said frame to oscillate transversely therein and having a cutting edge in front of and substantially in the plane of said foot-plate, a shafty rotatably mounted in said frame and havinga driving connection to said knife to oscillate the latter, and a pressure-plate mounted on said frame to engage the skin in front of the knife, the skin-engaging faces of both said foot-plate and said pressure-plate being provided with parallel ribs transverse to the cutting edge of the knife.

5, A derrnatome comprising a hand-holdable frame having a foot-plate to bear against the skin, a knife mounted in said frame to oscillate transversely therein and having a Cutting edge in front of' and substantially in the plane of said foot-plate, a shaftrotatably mounted in said frame and having a driving connection to said knife to oscillate the latter, and a pressure-plate mounted on said frame to engage the skin in front of the knife, the skin-engaging faces of both said foot-plate and said pressure-plate being provided with parallel ribs transverse to the cutting edge of the knife, the ribs on the skinengaging face of the pressure-plate being confined to the front portions thereof so that the rear portion thereof is unribbed.

6, A dermatorne comprising a hand-holdable frame having a foot-plate'to bear against the skin, a knife mounted in said frame to oscillate transversely therein and having a cutting edge in front of and substantially in the plane of said foot-plate, a shaft rotatably mounted in said frame and having a driving connection to said knife to oscillate the latter, a pressure-plate mounted on said frame to engage the skin in front of the knife and micro-adjustable relatively to the plane of the foot-plate and knife-edge, and spring-means for pressing the pressure-plate toward its support in said frame to prevent dis placement due to lost motion in the adjustment.

'7. A derni-atome comprising a hand-holdable frame having a foot-plate to bear against the skin, a knife mounted in said frame to oscillate transversely therein and having a cutting edge in front of and substantially in the plane of said foot-plate, a shaft rotatably mounted in said frame and having a driving connection to said knife to oscillate the latter, a pressure-plate mounted on said frame to engage the skin in front of the knife, the mounting of said pressure-plate on said frame being by a screw "at each end, and, each vscrew being micro-adjustable relatively to the plane of the foot-plate and knife edge, and a compression spring surrounding each screw and pressing the screw to one end of the lost-moti0n its threads permit.

8. A dermatome comprising a .hand-h'oldable frame having a foot-plate to bear against the skin, a knife mounted in said frame to oscillate transversely therein and having a cutting edge in front of and substantially in the plane of said foot-plate, -a means for reciprocating said knife,

al pressure-plate mounted on said frame to en.

plates mounted on said frame to underlie the end portions of the pressure-plate and knife-edge and adjustable relatively to each other to v-ary the width of the skin-surface exposed to the knifeedge.

9. A dermatome comprising a hand-holdable frame having a foot-plate to bear against the skin, a knife mounted in said frame to oscill'ate transversely therein Iand having a cutting edge in front of and substantially in :the pla-ne of said foot-plate, a shaft rotatably mounted in said frame yand having a driving connection .to said knife to oscillate the latter, a pressure-plate mounted on said frame to enga-ge the skin in front of the knive, and two guide-plate mounted on said frame to underlie the end portions of the pressure-plate and knife-edge, and a right-andleft-hand screw for adjusting said guide plates toward or from the center line of the frame to vary the width of the skin-surface exposed to the knife-edge.

10. A dermatome lcomprising a hand-holdable frame having `a. foot-plate to bear against the skin, a knife mounted in said `frame to oscillate transversely :therein and having a cutting edge in front of and substantially in the plane of said foot-plate, a shaft rotatably mounted in said frame and having ya driving `connection to said knife to oscillate the latter, a pressure-plate mounted on said frame to engage the skin in front of the knife and adjustable relatively to the plane of the foot-plate and knife-edge, and two guideplates mounted on said frame to underlie the end portions of the pressure-plate and knife-edge vand adjustable relatively to each other to vary the width of the skin-surface exposed to the knifeedge.

11. A dermatome vcompri-sing Ia hand-holdable frame having a foot-plate to bear against the skin, a knife mounted in said frame to oscillate transversely therein and having a cutting edge in front of and substantially in the plane of said foot-plate, ya shaft rotatably mounted in said frame and having a drivin-g connection to said knife to oscillate the latter, a pressure-plate mounted on said frame to engage the skin in front of the knife and adjustable relatively to the plane of the foot-plate and knife-edge, and a rightand-left-hand screw for adjusting said guideplates toward or from the center line of the frame to vary the width `of the skin-surface exposed to the knife-edge.

12. A dermatome comprising a hand-holdable frame havinga foot-plate to bear against the skin, a knife mounted in said frame to oscillate transversely .therein and having a cutting edge in front of and substantially in the plane of said foot-plate, means for reciprocating said knife, and a pressure member mounted on said frame in front of the knife and adjustable relative to the vplane of .the foot-plate, said pressure-member and foot-plate being provided with parallel, skin engaging ribs having well defined edges extending .transversely to the cutting edge of the knife.

13. A dermatome comprising a hand-holdable frame havingV a foot-plate to bear against the skin, a knife mounted in said frame to `oseillate transversely therein and having a cutting edge in front of and substantially in the plane of said foot-plate, means for reciprocating said knife, and a pressure member mounted on said frame in front of the knife and adjustable relative to the plane of the foot-plate, said foot-plate being provided with parallel, skin engaging ribs having well defined edges extending transversely .to the cutting edge of the knife.

HARRY M. BROWN. MILFORD BARRON.

REFERENCES CITED The following references are of record in the `file of this patent:

UNITED STATES PATENTS Certicate of Correction Patent N o. 2,457 ,772. December 28, 1948.

HARRY M. BROWN ET AL.

1t is hereby certified that errors appear in the above numbered patent requiring correction as follows:

In the grant, line 3, and in the heading to the printed speciication, lines 6 and 7, for the Word assignors read assigner; in the grant, line 14, for Irene Phillips Brown, her heirs read Milford Barron and Irene Phillips Brown, their heirs, as shown by the record oi assignments in this Oflice; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 3rd day of May, A. D. 1949.

THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

